It would be interesting to know if you get that message about the time the mount drops.

What that message looks like is the OS saying “rclone you are too busy”. Now what the kernel does after that I don’t know - it may kill rclone, or throttle it either of which could cause the mount to drop.

Ok, so I left my gdrive mounted all day and did not see the kernel message

Tried to copy the same file I have been using for testing, and yep the kernel message reappeared at around the same time that the finder showed the message about being unable to copy the file and the mount disconnected
(although mount still shows the drive as mounted, but trying to cd into the drive gives me a ‘Device not configured message’ so I need to umount the drive and remount to regain access.)